Electrochemical characterization of mixed matrix nanocomposite ion exchange membrane modified by ZnO nanoparticles at different electrolyte conditions “pH/concentration”

• PVC based/ZnO nanoparticles mixed matrix cation exchange membranes were prepared.
• Selectivity was improved by nanoparticles content increasing and then decreased.
• Flux was declined by increase of nanoparticles concentration and then increased.
• Conductivity was enhanced by increase of additive content and then declined.
• Selectivity/conductivity was changed by electrolyte pH/concentration variation.

In this research, novel PVC based nanocomposite ion exchange membrane was prepared by casting technique. ZnO nanoparticles were employed as semiconductor additive in membrane fabrication. The effect of nanoparticles concentration on properties of home-made membranes was studied. A relatively uniform surface for the membranes and uniform particles distribution were observed in SOM images. The membranes were characterized in different electrolyte conditions “concentrations/pH”. Results revealed that membrane water content, membrane potential, transport number and selectivity were enhanced initially by increase of additive concentration up to 10 wt% in membrane matrix and then showed decreasing trend by more additive loading. The ionic permeability and flux were also decreased initially by increase in additive content up to 5 wt%. The permeability and flux were increased another time by more increase in additive content. An opposite trend was observed for membrane electrical resistance. Moreover, membranes showed higher transport number and selectivity at pH 7 compared to other pH values. Membrane electrical conductivity was decreased by increase of pH value. Also membrane transport number and selectivity were initially enhanced by increase of electrolyte concentration and then began to decrease slightly at high electrolyte concentration.